(1) Get full path for the executable
Use SYS(16) or GetModuleFileName WinAPI function:

DECLARE INTEGER GetModuleFileName IN kernel32; 
	INTEGER  hModule,; 
	STRING @ lpFilename,; 
	INTEGER  nSize

e.g.: z:\app.exe

(2) Find if the executable is located on a remote drive
Use GetDriveType WinAPI function:

#DEFINE DRIVE_REMOTE  4
DECLARE INTEGER GetDriveType IN kernel32;
	STRING RootPath

(3) If the drive is not remote -- then SYS(0) is your answer.

(4) For a remote drive find name of the associated network resource
Use WNetGetConnection WinAPI function:

DECLARE INTEGER WNetGetConnection IN mpr;
	STRING    lpLocalName,;
	STRING  @ lpRemoteName,;
	INTEGER @ lpnLen

e.g.: \\myserver\group1
"myserver" is a computer name you are looking for